A police spokesman said 17 suspects of the violence were arrested. Thousands of Spaniards rallied in Colon square and center of Madrid on Saturday against poverty and EU-imposed austerity in a largely peaceful protest later marred by violent clashes with police. Unions joined student associations and other civil groups in calling for "marches of dignity" throughout Spain against cuts in social services and demanding the government to improve the economy, build a fair salary system, and strictly deal with corruption.